Composite tapes and fabrics are used extensively in aerospace, automotive, industrial and other engineered composites applications. These composite materials include, for example, continuous fiber reinforced thermoplastic (CFRT) tapes and fabrics. These tapes and fabrics are typically comprised of continuous reinforcing fiber; e.g. carbon fiber or glass fiber, and may be pre-impregnated or semi-impregnated with a polymer matrix.
Pre-preg is “pre-impregnated” reinforcing fibers where a thermoplastic polymer matrix material; e.g. HDPE, PP, PA-6, PA, PPS, PEI, PEKK, PEEK, is already present. The fibers, in this case, are continuous, whether a unidirectional tape of a woven one, and the matrix is used to bond them together and to other components during manufacture. Semi-preg is a partially impregnated form of pre-preg. The proper final fiber and matrix proportions are present, but they have not been fully melt-consolidated to create a pre-preg. Semi-pregs tend to be more flexible that pre-pregs, facilitating forming post-processes, but may require additional heat-consolidation process steps to form final components. Semi-pregs may utilize thermoplastic polymer powders or films that are partially melted to the reinforcing fibers to stabilize them and enable automated handling and welding by the methods described herein.
Because the fiber is continuous and in one direction within the tape, the tape may be oriented flexibly in different layers to build up a laminated component that includes a variety of directional fibers optimized to a particular design criteria. The resulting laminate has highly specific characteristics due to the variety of fiber orientation throughout. Engineered solutions that could not otherwise be achieved by materials with homogeneous properties (e.g. metals, short fiber reinforced plastics) are thus realized by CFRT tape.
CFRT tape is an engineered composite material that enables the engineering of composite structure design, but is not easily converted to finished components. Continuous fiber, as opposed to long, short, chopped and other discontinuous forms, provides superior mechanical properties in an efficient form, thereby reducing the quantity of material utilized to meet a particular structural goal. Mass reduction of finished components is therefore often realized by utilizing continuous fiber in tape form.
The aerospace industry has evolved from wood and canvas, plywood (early composites), and metals to advanced composite materials. Manufacturing technology has matured more quickly for thermoset (epoxy) CFRT tape systems, while that of other composite tape materials has lagged behind. A common, although low-volume manufacturing method of utilizing continous CFRT tape is to melt-consolidate multiple layers together in a heated press system of some set configuration, including continuous systems, e.g. CCM (Continuous Compression Molding). The resulting melt-consolidated panel may have multiple nested parts cut from it, which are subsequently individually heated back up to melt, then compression molded or formed to a finished shape or geometry. This final part may then be overmolded with short-fiber reinforced or unreinforced thermoplastic to add fine details that do not require continuous fiber. Melt-consolidation, machining, compression molding, and overmolding are well understood in most cases and these processes have achieved a level of maturity. They do not address however, the bottleneck of feeding CFRT tape at high-volume into the consolidation process. Current manual practices and machines cannot be scaled for high-volume production.
Similar to the aerospace industry, automotive and industrial applications are advancing in composite materials adoption. CFRT tape formatting processes and downstream conversion processes (lamination and consolidation) offer a step-change toward replacing metallic structure with composite structure. Engineered component designs utilizing CFRT tape enable the optimized structures for strength, crash-safety, and mass reduction of systems throughout the vehicle platform.
CFRT tape products from multiple suppliers have matured to a level of quality that allows for automation of manufacturing processes that convert the incumbent form of these materials into ones that allow for higher volume and quality manufacturing of finished goods. This improved material quality, industry awareness of utilization of these materials, overall growth and maturity of composite materials in a variety of applications, are all creating the need for specific forms of materials to enable widespread adoption. Slow, manual methods used to make these materials today lead to worker injury, limited production, inconsistent quality, and the lack of advancement of downstream automated manufacturing processes.
A need therefore exists for a more automated, safer, higher-throughput process of manufacturing high quality rolls of oriented fiber CFRT tape as well as for other composite material tapes, for use as feedstock to high-volume lamination and consolidation processes.